The specific aims of the Vector Core for his PPG proposal are to I) prepare working stocks of previously generated recombinant viruses for investigators to perform gene transfer experiments, ii) test all viruses for helper virus and pfu/particle ratio, iii) assist in the evaluation of initial gene transfer studies by helping set up molecular and/or enzymatic assays. By providing these services, the Vector Core substantially reduces the overall cost and time of setting up routine vector production in each investigators laboratory.